The objective of this research program is the elucidation of the normal and abnormal physiology of a newly-discovered human growth-promoting hormone, human Epidermal Growth Factor (hEGF), which is probably identical to urogastrone, an antiulcerogenic factor also recently isolated from human urine. Human EGF will be extracted and purified from human urine in sufficient quantities to use for immunization and further physicochemical and biologic characterization. Existing hEGF radioimmunoassays will be used to measure urine EGF excretion under a variety of conditions in normal subjects and in patients with ulcer disease and a variety of conditions associated with epithelial hypoplasia, hyperplasia, dysplasia, neoplasia, regeneration and repair. More sensitive hEGF radioimmunoassays will be developed in order to measure plasma hEGF as an index of acute changes in hEGF secretion. The radioimmunoassay and the immunoperoxidase bridge technique will be used to establish hEGF's tissue/cell of origin. The effects of hEGF on gastric acid secretion and gastric arterial blood flow and the mechanism of its antiulcerogenic activity will be studied in appropriate animal models. Ultimately, we hope to investigate the metabolism of labeled hEGF in humans and its therapeutic efficacy in peptic ulcer disease and in conditions requiring epithelial replacement and repair.